Aloysius "Alois" Alzheimer (1864-1915) was a German psychiatrist and neuropathologist and a colleague of Emil Kraepelin. In 1906, Alzheimer made a complete clinical and pathological description of presenile dementia, which came to be known as Alzheimer's disease, a progressive condition in which nerve cells in the brain degenerate. In 1915, Alzheimer became ill while traveling on a train. Most probably he had a streptococcal infection and subsequent rheumatic fever and kidney failure. He died of heart failure at the age of 51.